The present invention pertains to systems for preparing and delivering fluids to an artificial kidney in a controlled manner.
All artificial kidney systems have a common objective of removing toxins and excess body fluids from the bloodstream of a kidney-failure patient. Toxins are removed by dialysis, which is a chemical diffusion process using a semipermeable membrane which selectively permits the toxins to pass from the blood into a chemical solution referred to in the art as "dialysate". Excess body fluids are removed by developing a pressure differential across the semipermeable membrane (referred to as the "transmembrane pressure" or "TMP") which forces water molecules to pass from the blood into the dialysate.
Such basic functions occur in the artificial kidney or "dialyzer" portion of the system, the principal elements of which are the semipermeable membrane, input and output ports for the patient's blood, and input and output ports for the dialysate solution. The artificial kidney is an electrically passive component of the system, which works in response to the pressure of the fluids passing through its ports coupled with osmatic action in a manner known in the art.
The machine which delivers the dialysate solution to the artificial kidney is a complex electro-mechanical apparatus which functions within tightly controlled limits and which monitors various safety parameters. The present invention is directed to such a machine and to dialysate delivery systems in general.